With the development of social economy, great changes have taken place in people's life style and dietary choices, which thus results in dramatic changes in spectrum of diseases, and chronic non-infectious diseases are becoming prominent problems endangering people's physical and spiritual health. Among these diseases, hyperglycemia, hyperlipidemia and leukaemia are on the rise, and epidemiological studies have shown that hyperlipidemia, hypertension and diabetes are closely associated with atherosclerosis. More seriously, hyperlipidemia, hypertension and hyperglycemia often come together, which has gradually become one of the important health hazards worldwide.
As one type of commonly used CMM, raw Rehmannia glutinasa Libosch. is the fresh tuber of Rehmannia glutinasa Libosch of Scrophulariaceae family with wide clinical applications, such as treating hematologic diseases by enriching, cooling and regulating blood. As known in China, Rehmannia glutinasa Libosch. is usually used for treating such diseases as heat diseases and deep-red tongue, interior heat and diabetes, efficiency of liver-yin and kidney-yin, hectic fever and so on. In recent years, many researches have been carried out on the chemical composition and pharmacological action of Rehmannia glutinasa Libosch. It is reported that Rehmannia glutinasa Libosch. has various biological activities on the systems of immune, endocrine and blood, the cardio-cerebral vascular system, the nervous system and so on. As the main components, phytosterols, carbohydrates, amino acids, iridoid glycosides such as catalpol and the like are included in Rehmannia glutinasa Libosch. 
After extensive studies and experiments, the present applicant found that as one type of main components in Rehmannia glutinasa Libosch., iridoid glycosides such as catalpol and the like are highly polar compounds with similar chemical structures, which have low chemical and thermal stability and are difficult to be extracted and separated. As a result, there is no Rehmannia glutinasa Libosch. extract in the existing products that has a definite main effective composition, contains high content of catalpol, and has high stability and reliable efficacy in reducing blood glucose and blood lipid.